Using the Theory of Planned Behavior to determine COVID-19 vaccination intentions and behavior among international and domestic college students in the United States

Vaccination is the most effective strategy for preventing infectious diseases such as COVID-19. College students are important targets for COVID-19 vaccines given this population’s lower intentions to be vaccinated; however, limited research has focused on international college students’ vaccination status. This study explored how psychosocial factors from the Theory of Planned Behavior (TPB; attitudes, perceived behavioral control, subjective norms, and behavioral intentions) related to students’ receipt of the full course of COVID-19 vaccines and their plans to receive a booster. Students were recruited via Amazon mTurk and the Office of the Registrar at a U.S. state university. We used binary logistic regression to examine associations between students’ psychosocial factors and full COVID-19 vaccination status. Hierarchical multiple regression was employed to evaluate relationships between these factors and students’ intentions to receive a booster. The majority of students in our sample (81% of international students and 55% of domestic students) received the complete vaccination series. Attitudes were significantly associated with all students’ full vaccination status, while perceived behavioral control was significantly associated with domestic students’ status. Students’ intentions to receive COVID-19 vaccines were significantly correlated with their intentions to receive a booster, with international students scoring higher on booster intentions. Among the combined college student population, attitudes, intentions to receive COVID-19 vaccines, and subjective norms were significantly related to students’ intentions to receive a booster. Findings support the TPB’s potential utility in evidence-based interventions to enhance college students’ COVID-19 vaccination rates. Implications for stakeholders and future research directions are discussed.


Introduction
In this part, the authors summarized the prevalence of covid-19 infection in the US and the benefits of covid-19 vaccination.In addition, there have had some studies on the awareness and attitude of covid-19 vaccination among young people including students at colleges in which the rate of covid-19 vaccination in this group is still low due to many reasons such as distrusting vaccines, worrying its side-effects, believing in natural immunological system, etc. Especially, applying the theory of planned behavior (TPB), including attitude, behavioral intention, perceived behavioral control (PBC), and subjective norms to search for an answer as to whether psychosocial factors are involved with covid 19 vaccination among domestic and international college students.

Theoretical Framework
Although the author mentioned the TPB theory by using the tool to research on the attitudes and behaviors of students in vaccination against influenza and HPV, the study aim in this paper was the attitudes and behaviors of students in vaccination against the covid-19 virus, a very new, causing a pandemic, unknown side effects of the vaccine, ... TPB of covid-19 vaccination is very different from that of vaccination against influenza or HPV, an age-old vaccine and its effectiveness as well as side effects have been proven.Therefore, the author should present the theoretical part of TPB on vaccination against covid 19 in which attitude, behavior intention, subjective norms, and PBC are related to covid-19 vaccination.

Method and materials
In this part, it is good at that author presented variables such as attitude with possible scores (7 -49) and Cronbach' alpha value (0.93 for international students and 0.89 for domestic students); behavioral intention with possible scores (3 -21) and Cronbach' alpha value (0.98 for international students and 0.92 for domestic students); PBC with possible scores (6 -42) and Cronbach' alpha value (0.85 for international students and 0.86 for domestic students); subjective norms with possible scores (4 -28) and Cronbach' alpha value (0.94 for international students and 0.82 for domestic students).Moreover, binary logistic regression and hierachical multiple linear regression were applied to analyse data.

However, authors should clarify and present more information:
-The way to choose sample size in which how many international and domestic students at colleges in the USA are studying.For example: there are 1,1 million international students in USA, but a sample size of 197 students were counted in the study.
-The way to develop the TPB-based instrument includes pilot studies of qualitative and quatitative, expert panel review, pilot test, test retest, internal consistency, construct validity, and predictive validity assessment.
-An exploratory factor analysis (EFA) is used to determine the number of factors and percentages of explained variance which extracted factors according to eigenvalues greater than 1.0, factor loading higher than 0.5, and used processes of principal components factor and orthogonal rotation.In addition, confirmatory factor analysis (CFA) is applied to evaluate the validity of the health belief items.A value of factor item loadings at or above the 0.3 level was considered significant in factor analysis. - The goodness-of-fit indices were used to assess the observed model and the theoretical model or the final structural model exhibited acceptable fit of the data -Explaining more clearly the block 1 and block 2, are they the same model 1 and model 2? Results -Research results are interpreted in 4 main points (participant characteristics, TBP-based psychosocial factors, determinants of receiving full COVID-19 vaccines, and determinants of intention to receive a COVID-19 booster) with tables 1-4.This result answers the objective and hypothesis study.-However, before presenting results, author should interpret the stages of the TPB-based instrument development including pilot studies of qualitative and quantitative, expert panel review, pilot test, test retest, internal consistency, construct validity, and predictive validity assessment.